Genco Initiatives

O&M practices by TPPs to maintain equipment health and performance

The operations and maintenance (O&M) of thermal power plants (TPPs) is critical to guarantee that they operate efficiently and without in­terruption. Adopting effective O&M me­thods has become essential in the coal-based power generating segment, given the constraints of a shifting fuel mix, fle­xible operation and tougher environ­me­ntal and safety requireme­n­ts. Best O&M practices at TPPs help not only in achieving high levels of performance, but also maintain the health of the power plant equipment. For effective O&M, real-time monitoring of im­portant parameters, predictive and preventive maintenance and condition-based monitoring are gaining traction. Furth­er, machine learning, artificial intelligence and data analytics can offer several benefits.

Power Line takes a look at some of the O&M practices adopted by major central, state and private generating com­pa­nies (gencos)…

Gencos’ O&M initiatives

NTPC Limited: Cycling of plants, ancillary services requirement, frequent load following and ramping in short range cause stresses due to creep and fatigue loading. For this, one focus area is auto­loop control tuning of control systems and advanced control measures, with additional condition monitoring systems. NTPC is implementing one digitalisation package across the company, an advanced analytics and visualisation platform, for integration and consolidation of all the data. It has also awarded another package for real-time diagnostics and an advisory support system that would use advanced pattern recogni­ti­on technique for early warning for incipient faults, thereby facilitating continuous monitoring of the health and performance of the equipment. The utility has adopted a fatigue monitoring system to monitor the condition of thick wall pressure parts and life of these components. Besides this, NTPC is also looking at ro­botics and drones, chimney inspections, edge-type inspections, and coal yard mapping, among others. As original eq­ui­p­ment manufacturers (OEMs) may move to renewable energy, they may gradually withdraw from manufacturing and may not provide adequate support for spares and services for TPPs. There is a concern regarding balance of plant facilities, namely, coal handling plants, ash handling plants, or aerated bearings where the actual requirement number may not be very high. So, there would be a need to import these high-cost bearings from abroad, with a high purchase lead time. So, on a policy basis, it is im­perative to incentivise and develop alternative resources for spares of TPPs, for continued reliable operations.

Mahagenco: Maharashtra State Power Generation Company Limited (Maha­ge­nco) has developed standard operating procedures and an expert team for effective O&M practices. The utility has adopted a three-point programme, wh­ich includes efficiency improvement, environment protection for reduced carbon footprint, capacity addition and energy services and consultancy. Nota­bly, a decline in coal quality, which is ha­ppening today, affects the boiler and ca­uses erosion and boiler tube leakage. There­fore, Maha­gen­co now uses washed coal for efficiency improvement. For flexible operations, the utility is in talks with OEMs. Further, it is giving priority to im­proving reliability, minimising auxiliary power consumption effective utilisation of all resources, and safety of man and ma­chines. For environment protection, it has adopted the 3Rs – reduce, reuse and re­cycle. The water consumption in Ma­ha­genco’s TPPs is well below limits. The utility uses water from sewage treatment plants at the Koradi and Kha­perkheda TPPs and plans to adopt the same at more TPPs are also under way. Moreover, it is working towards up­grading the skills of its em­ployees throu­gh courses available at their centres in Nasik and Koradi.

Adani Power: Adani Power has adopted a data-driven approach to O&M since 2012. It has adopted DISHA, a business process transformation initiative focus­ed on power business operations to integrate all its processes in the IT-enabled platform. The objective behind DISHA is to establish sustainable practices in O&M, fuel management, strategic planning and revenue management; manag­ement information system and human resource processes of global standards through operating model redesign; and process definition and implementation, including IT enablement. The company has introduced reliability-centred maintenance across all stations. Further, safety remains a major focus area for which it has been working with DuPont to achieve “Zero Harm” through “Project Chetna” at all its stations. It follows stringent key performance indicator (KPI) monitoring on a day-to-day basis. For spare management, the company relies 70-80 per cent on indigenously developed spares since 2015. The company also has an energy network operation centre in Ahmedabad, wherein integrated data is collated and analysed for decision-making.

JSW: Currently, utilities are doing too much maintenance. For example, for tur­bine overhaul, it is opened every three to five years, while in Europe and the US, these are opened once in 10 years. Fur­ther, these regions have adopted online pumping. Similarly, for condensers, these are opened every two to three years. To avoid too much maintenance, utilities sh­ould adopt risk-based maintenance. Du­ring flexible op­e­rations, low load results in more fati­gue, for example, as in the case of the Ratnagiri and Vijayanagar TPPs. For this, we have traditionally relied on radiography, but a renewed focus should be placed on non-destructive tests, which can be carried out on selected components. This may include pha­sed array ul­tra­sonic testing or mixing with eddy current to ascertain the da­ma­ge. Pre­vi­ou­sly, the lube oil systems were drained and lubricants were replac­ed during each major plant outage or shutdown, but the life of lubricants is 25 years, hence, there needs to be a replacement criterion in place. There is a need to adopt KPI-based maintenance rather than manpower-based maintenance. Although a lot of reverse engineering has been done for metallurgical and mecha­nical aspects, there is still a long way to go for electrical and electronic aspects. Going forward, turbine cooling, turbine washing and pump cleaning for upper base deposits are required. As per the recent annual report of JSW, during the Covid-19 pandemic, the company de­mons­trated the capability of remote handling of O&M operations, through a full-fledged set-up of human-machine interface stations at the respective townships of energy plants. This resulted in timely support of operations, delivered remotely during the pandemic period.

Outlook

The energy landscape is undergoing a major change in the country. As TPPs are preparing for flexible operations, they are transitioning to cyclic operations as against baseload operations. This will lead to faster deterioration of plant components, higher O&M expenses due to the reduced life of components, additional costs owing to an increase in the heat rate and auxiliary power consumption, and an increase in oil consumption on account of frequent starts/stops. Therefore, utilities are required to adopt best-in-class O&M practices to achieve business excellence and ensure long-term economic viability.

To keep the cost of generation low, activity-based budgeting and cost-cutting measures, as well as optimal fuel mixing are required. Root cause analysis, reliability-centred maintenance, multi-year overhaul plans, zero-forced-outage stra­tegies and systematic inventory management are some of the key mainte­na­n­ce procedures being deplo­yed by utilities to improve their O&M practices.

Utilities should aim to reduce start-up time to achieve operational excellence and maximise plant availability and load factors. Overall, the adoption of new and innovative technologies, cost savings and work mechanisation should be prioritised. Capacity building and tr­a­ining could also enable TPPs to im­pro­ve their O&M. Furthermore, best practices in O&M enable reliability of power plants, help maintain plant safety and availability and enhance asset flexibility, while keeping maintenance costs at a minimum. Going forward, utilities sh­o­u­­ld adopt tailored O&M strategies ba­sed on their requirements. n

Based on a panel discussion among Achal Kumar Arora, General Manager, Operation Services-SIIS, NTPC Limited; Abhay Harne, Chief Engineer and Executive Director (additional charge), Mahagenco; Ashesh Padhy, Senior Vice-President, JSW Steel; and Girish Raghuwanshi, Associate Vice-President, Adani Power, at a recent Power Line conference

GET ACCESS TO OUR ARTICLES

Enter your email address

Share your work e-mail and access a free 3 month digital subscription to Power Line Magazine